Wireless signaling apparatus.



L. DE FOREST. I WIRELESS SIGNALING APPARATUS.

APPLICATION FILED JAN.17.1903- L Fig-1.-

W/TNESSES:

/NVENTOH y 4% azzzw A; A 770mm PATENTBD JULY 28, 1908.

UNITED STATES PATENT OFFICE.

Lon on roncsw or NEW YORK, N. Y., ASSIGNOR TO DE roans'r RADIO TELEPHONE COMPANY, A CORPORATION or NEW YORK.

WIRELESS SIGNALING- APPARATUS.

Specification of Letters Patent.

Patented July 28, 1908.

Application filed January 17,1903. Serial No. 139,404.

the city of New York, borough of Manhattan,

in the county and State of New York, have invented certain new and useful Improvements in irelesssignaling Apparatus of which the following is a specification.

My invention relates to improvements in wireless signs ing apparatus whereby a multiple syntony'may be employed in communicating signals, that is more than one set of differently tuned Wave trains may be used, the receiving apparatus responding only when wave trains of both frequencies are received.

My invention consists of the novel parts and combinations thereof hereinafter described and particularly pointed out in the claims.

Figures 1, 2 and 3 show different forms of receiving apparatus embodying the principle of my invention, and Fig. 4 shows a form of transmitting or sending apparatus-adapted for use with my invention.

The accom anying drawings illustrate my invention in forms now preferred by me but do not illustrate ;all the forms in which it may be embodied. They are however sufficient to make clear the principles of my invention. These each show a plurality of separate and diflerently tuned wave collecting systems, a corresponding number of coherers or other wave-responsive devices and a common receiving or indicating instrument which is so designed and connected with the various Wave-responsive members that it is operated only when all of them are affected, each by waves of the frequency corresponding with that for which its receiving system is designed. By this plan the number of sets of instruments or stations within the same field of influence which may be simultaneously operated without interference, may be.largely increased. I have herein only shown apparatus designed for operation bytwo sets of tuned waves of dilferent periods but it is evident that the principle may be amplified so as to require a greater number of sets of wave trains to operatethe' apparatus. f1.

- Bteferring to Fig. 1, A and Brepresent two wave collecting or receiving conductors, each designed to be syntonic with a wave train of wave-responsive devices.

a articular period, but such wave trains di ering in period from each other. To each of these antennae or wave-collectors is connected a receiving circuit or conductor tuned to the same frequency. The form of'this receiving circuit or conductor is immaterial provided that it has the selective quality which causes it to respond to waves of its particular frequency While being unrespons1ve or poorly responswe to wave trams of other frequency. I have herein shown for such receiving c1rcu1ts, parallel conductors as a, a and b, b}, constltutmg what is known 1n the art as Lecher conductors, as I have found such conductors to possess the desired selective uality in a high degree. The corres on din ends of the two conductors forming t e Lec er conductors are connected, one with the antenna and the other with the earth or other capacity. Between these conductors at theirothcr ends or at any other oint where occurs a loop of waves ,of' the liind (electro-static or clcctro-magnetic) by which thawave-responsive device is designed to operate, is placed such wave-responsive device 'as" R, R, It.

A single indicating or receiving instrument is shown which is common to all the This receiving in strument' may be of any desired form. That herein shown is a telephone receiver. In Fig. 1 I have shown two-local circuits having a common branch; in which is located the 10- cal battery G. I- have also shownqchoke coils K in such circuits adjacent the wave responsive devices. The local circuit or circults may contain any desired or necessary apparatus of the usual construction except as otherwise herein stated.

The indicating or receiving instrument contains a coil or-coils adapted, when energized as the result of waves received from the respective receiving circuits, to similarly affect saidinstrument 'to produce a signal. This is designed so that a single set of wavesreceived through one of the receiving circuits is not of sufficlent ower to clearly produce the signal, while if wave trains of the frequency of both receiving circuits are simultaneouslyreceived they will act alike u on the receiving instrument to produce a 0 car signal.

In the receiver F of Fig. 1 the two coils f and f are each in their respective circuits and act elike upon the diephraguif In Fig. 2 a single local circuit is used, in which are both wcve responsive devices it and it in series and 9. single coil is used. In this figure as Well as in Fig. 3 when more than one ground E is shown, one ground connection is provided with e condenser C to permit pcssage of the aerial waves, While preventing short circuiting the local buttery byway of the grounds.

The apparatus of Fig. 3 is like that of 1, except that a third antenna B and its receiving system is employed, this system be ing e-periodic or untuned, While the others are periodic or tuned after the manner previously described. This third antenna is connected with the earth by an a-periodic conductor 6 which. contains at wave-responsive deviceR The local circuit for this speriodic system contains the coil f which should be of sufiicient power to overcome the added effect of the coils f and f in both tuned circuits.

A powerful, strongly damped or e-periodic Wave train possesses the power of forcing vi bretions in any circuit whether tunedor untuned. it will therefore produce an eii'ect in each of the coils tending to operate the receiying instrument. As the ell ect oi the coil 30 f of the a periodic circuit is equal to that of the coils in both or all the other circuits, the operative eiiect caused by such ext-periodic Wave train is nothing. The apparatus will then be protected sgeii t the disturbing effectfiof un tuned or e-periodic wave trains.

The transmitting sppcratus shown in Fig. 4 is indicative only of a type of such upperstus which may be employed. In. this 1 have shown three separate radiating antennae A, A, and B The entennm A and A are differently tuned, each corresponding with its receiving circuit or system, which are herein shown as consisting of Lecher conductors a, a and b, b. Period iidjusting or controlling devices such condensers l or any other form of device may be connected with these receiving systems.

I have shown an alternating generator l? as the source of Ql(B(Jl11'O..I310tlV-c force, this being connected with each of the tuned systems consisting of the liccher conductors by nieensof two sets of transformer coils T, 'i. The spark gaps S and S are pieced in the corn ductors between the tivo tinnsforiners. The oscillating circuit which is connected with the spark gap is shown as provided with con densers C by which its period may be dotermined. By this or any other suitable meensthe two systems tuned to dill'crent )eriods' Both of these tuned circuits may, f desired, be connected with the some rsdisting antenna. The key l for producing the signal is placed in the primary leading from the generator.

The c-periodic radiating system, when one is used, is substantially the seine as above ,i described, the antenna B being however directly connected with the sparking circuit and no key being used. sends out a continuous series ofa-periodic waves which will interfere with the receipt of l e'signal by any apparatus not protected after the enner shown in Fig. 3 and herein described. If desired the e-periodic antenna may be comiected with the some generator us is employed to energize the periodic systems, as is indicated by dotted lines.

By the use oi apparatus embodying the principles nboveset forth, the scope of syntonic telegraphyis vastly enlarged inasmuch as in practice it has been found impossiblev to ent frequencies in the some zone ofinfluence, since, unless these frequenc es differ from each other by a very considerable number of waves will overlap or intrude upon those nearest in tune with itself.

By the method of double tuning herein described, I can however, simultaneously oper ate in. the same zone and Without interference, a number of additional systems equal to. the number of sets or combinations of pairs possible from all th non-interfering single systems. It is obvious that the same principle n'iuy be extended to embrace three or even more d stinct resonic systems connected to one and the seine receiving or recording device, said device not operating save when the required number of wave trains properly at" -ned, be simultaneously received. The number of stations thereby co )ublc of being operated in the some zone of in -uence is made practically unlimited.

At the sending station it is only necessary toms, similarly attuned, each with its own or o connnouredieting antenna, and to one!- gize all from a common source of power through a. common key.

lluving thus fully described my invention, whet 1 claim as new end desire to secure by Letters Patents is:

1. In nspnce signaling apparatus, theco1nbinution with u sending device having a plurulity of wave producers, each having a, period diil'cring from the others, of a. receiving mental wave responsive devices, and an indicating device connected with all of said wave responsive devices.

In, a SPll-CG signaling apparatus thecombinntion with a sending device 'hovingz, plurelity of wave producers each having a period differing from the others, of a receiving apparatus having a plurality of'und compleing device and connections therefrom to all 1 ol sand wove responsive devices adapted to 1 operate the indicating device only when a.

This antenna thus I e f use at large number of stations hevlng d1fier frequencies per second, one set of signal to employ an equal number oi" resonic sys-' ment'cl Wave responsive devices, on indicet apparatus having a plurality of and compleplurality of the wave producing devices are energized, each by its corresponding wave' train. i

3. In space telegraphy the combination in a sending apparatus of a plurality of cooperating Wave prodncin devices, one adapted to produce a series 0 aeriodic waves and the others adapted to pro uce periodic waives. 4;. In spzice tele raphy, the combination?- with a plurality of ifferently tuned r'eceiving systems, and an a-periodic receiving system,

of a receiving or indicating instrument, means whereby said receiving instrument is operated by the joint action of waves simultaneously received upon all the tuned sys tems, and means whereby waves received by the untuned system affect the receiving instrument oppositely to those received by the tune systems. I I.

5. In a receiving system of space communication, the combination with a plurality of antennae each made syntonic with a wave train ofn particular period, of'a plurality of Lecher receiving conductors 'eech connected to and tuned to the same frequency as the res ective antennae; a. corresponding number 0 wave-responsivedevices; and common indicating means connected therewith to be operative only by all of said! wave-responsive devices.

lation producing circuits, of a plurality of wave-producing means cooperating and resonant with the respective oscillation-producing circuits, at least one of said Wnvepro 6. In a sending system of SPSJCO'GOIHIIIUDI cation, the combination with a 'ilurality of relatively frequency-a ljustable CIOSBd osci1- ducin means includin a Leclier conductor. 7

In testimony whereof, I have hereunto at? fixed my signature this 9th day of January 1903, in the presence of two witnesses.

I H LEE DE FOREST. Witnesses:

I. R. D. PHELPS,

W. B. BROOKE. 

